Tamiya 89916 4-Speed Crank-Axle Gearbox Kit - Clear

This gearbox has four possible gear ratios, including the highest gear ratio of Tamiya’s gearbox series, 5402:1. The other options are 126:1, 441:1, and 1543:1. This gearbox also features a worm gear, which locks the output shaft when the motor is not turning.

Adam, who posts under the username nexisnet on the Pololu forums, has performed a detailed series of experiments to determine how operating voltage affects the lifetime of the Mabuchi FA-130 motor, which happens to be the motors used in the Tamiya 70168 Double Gearbox, 70167 Single Gearbox (4-Speed), 70097 Twin-Motor Gearbox, 70093 3-Speed Crank-Axle Gearbox, 70110 4-Speed Crank-Axle Gearbox, and 70103 Universal Gearbox.